Thursday, October 28, 2010

Odd Star Sheds Cometlike Tail

In fact, Mira is speeding through the galaxy at 291,000 miles (468,000 kilometers) an hour—an unusually fast clip that may be the result of gravitational boosts from other passing stars.

Mira's supersonic speed causes a type of shock wave known as a bow shock to form in front of the star, study co-author Mark Seibert, from the Observatories of the Carnegie Institution of Washington in Pasadena, explained at the briefing.

The material in Mira's tail was shed over the past 30,000 years. Studying the tail will allow scientists to understand how stars like the sun die and seed new solar systems in the process, Caltech's Martin said.

Mira is a common type of star, Carnegie's Seibert added, and even though the cometlike tail phenomenon has never been seen before, the behavior is likely widespread.

Michael Shara is a curator at the American Museum of Natural History in New York and a professor of astronomy at Columbia University.

He was not involved in the study but participated in the briefing to offer perspective on the discovery.

"It's giving us this fantastic insight, I think, into the death processes of stars and their renewals—their phoenix-like revivals as their ashes get cycled back into the next generation of stars," Shara said.